A child's stroller with a stars and stripes balloon attached is left after gunfire erupted at a Fourth of July parade route in the wealthy Chicago suburb of Highland Park, Illinois, U.S. July 4, 2022 in a still image from video. ABC affiliate WLS/ABC7 via
A child's stroller with a stars and stripes balloon attached is left after gunfire erupted at a Fourth of July parade route in the wealthy Chicago suburb of Highland Park, Illinois, U.S. July 4, 2022 in a still image from video. ABC affiliate WLS/ABC7 via REUTERS . Reuters / WLS-TV/ABC7

An Illinois man accused of opening fire on spectators watching an Independence Day parade in a Chicago suburb last month pleaded not guilty on Wednesday to 117 counts connected to the attack, including 21 charges of first-degree murder, the state prosecutor said.

The suspect, Robert Crimo, 21, made his plea on a grand jury indictment during an arraignment hearing in front of Lake County Circuit Court Judge Victoria Rossetti, the office of Lake County State Attorney Eric Rinehart said.

Crimo was shackled at the waist and wore a blue jail jumpsuit and a surgical mask over his face during the brief hearing, the Chicago Sun Times reported.

His next court date is Nov. 1, according to online court records.

He has been held without bail since he was arrested after the shooting at the July 4th celebration in Highland Park, Illinois, which left seven people dead and more than three dozen injured. If convicted on the murder charges, he would face a mandatory sentence of life in prison without the possibility of parole.

The bloodshed was part of a recent flare-up of mass shootings in the United States, which has stoked a long-running debate between advocates for tighter controls over gun ownership and those who oppose any restrictions on the constitutional right of Americans to bear arms.

Two of the most prominent of those attacks took place at a school in Uvalde, Texas, where a gunmen shot and killed 19 children and two teachers, and at a supermarket in a predominately Black neighborhood of Buffalo, New York, where a shooting rampage left 10 people dead.

The Highland Park suspect had planned the attack for weeks, prosecutors said. On the morning of the parade, he climbed on to a rooftop along the parade route and fired more than 70 rounds at spectators lining the street below, according to court documents. He then made his getaway dressed in women's clothing and makeup to cover his facial tattoos.

A Smith & Wesson semiautomatic rifle, similar to an AR-15, was found at the scene, and a similar weapon was in a car driven by the suspect when he was arrested, according to prosecutors.